Wind density & effect on a kite or sail

[kitcho207]

Hey,

 

 

 

this is myfirst post. Im simon from sydney australia.

 

 

 

i have a question that is running around my kitesurfing forum about how the ambient temperature effects the power behind the wind. So 30knots of wind at 2 degrees Celsius compared to 30knots at 25 degrees Celsius. most of the people on their understand the density changes due to the temp, therein lies our main question...does a cold wind have more power at the same wind speed.

 

our kites average from 6sq meters to 19sq meters. would there be any noticeable difference?

thanks in advance for any light shed. please when replying remember we are notthe brightest bunch, lol. So keep the answers to what the average joe will understand.

 

 

 

Cheers

 

simon

[CaptainPanic]

Excellent question.

 

What matters is that the density of the air is not the same. Here is a table (wikipedia) that gives the relation between the density of the air and the temperature at a pressure of 101.325 kPa, or 1 atm.

 

You can see that the difference in air density between air at +2 C and +30 C is about 10%. If the velocity of the air is the same, if the pressure of the air is the same, and if your kite is the same, then cold air should create a larger force because your kite is catching a larger mass of air per time.

 

However, you should note that the air pressure is not constant! The difference between high pressure days and low pressure days can be almost as large. The pressure is linearly related to the density of air. And air pressure can also easily change 5% between high and low, and even more in extreme cases. Sunny days tend to be high pressure. Cloudy, rainy days tend to be lower pressure, and the lowest pressure occurs in storms (and esp. hurricanes).

[kitcho207]

Hey. Thankyou very much for that clear and easy to understand answer. Ill pass it on to the troops.

 

Cheers

Simon